Abstract

Background: Skin cancers, including both melanoma and keratinocyte carcinomas, are the most common cancers diagnosed in Australia. Solar ultraviolet radiation, sunlight, is a skin carcinogen. Geographical regions of north Queensland (Australia) are exposed to high levels of solar ultraviolet radiation year-round. For Caucasian populations, excessive exposure to solar ultraviolet radiation, especially during the childhood years, can result in sunburn and increase melanocytic naevi development. Naevi are a risk factor for melanoma and have been identified as precursor lesions in up to 60% of melanoma cases. Therefore excessive sun-exposure during the childhood years can increase naevi development and lifetime melanoma risk. The risk of developing melanoma may be especially high for individuals with numerous naevi, a history of painful blistering sunburns during childhood, fair skin (Fitzpatrick skin type I or II), fair hair colour and light eye colour. The risk of developing keratinocyte carcinoma, for example basal cell carcinoma, is linked with both intermittent and excessive sun-exposure, particularly excessive exposure that resulted in sunburn during childhood. School children should be encouraged to use multiple methods of sun-protection, including hats and shade, when outdoors at school to reduce excessive exposure to ultraviolet radiation.

The sun-protection policies of north Queensland primary schools and the sun-protective practices used by children and their adult role-models (including parents and school staff) at these schools are not regularly monitored and reported. Also, these school communities are not required to measure and report the amount of shade available at their school for children to use when they are outdoors. At the commencement of this thesis the comprehensiveness of north Queensland primary school sun-protection policies and how well these school communities followed through with sun-safety guidelines had not been documented. A remote (off-site) method to accurately measure shade at schools was also unavailable.

The aims of this thesis were to address the following research questions.

2) What body surface area is covered by regulation school uniforms at primary schools in Townsville, Cairns and the Atherton Tablelands (study 2)?

3) Can a method to remotely measure shade availability at schools be developed (study 3)?

4) What proportions of Townsville primary school students and their adult-role models wear a hat to school before, during and after school hours (study 4)?

5) What proportions of Townsville primary school student spectators wear a hat and wear a shirt at inter-school swimming carnivals (study 5)?

Methodology: Participants: All north Queensland schools catering for primary school aged students (generally 5-12 year olds) from Townsville, Cairns and the Atherton Tablelands were included in studies 1 and 2 while a sample of these schools were included in studies 3 to 5. For studies 4 and 5, schools were included if they were located within a 15 km radius of Townsville's Central Business District, had at least 60 students enrolled in 2008, and predominantly educated 'day' students (not exclusively boarding schools).

Education Queensland school directory lists were used to identify eligible schools in Townsville, Cairns and the Atherton Tablelands. The SunSmart status of each school was verified through email contact with the Cancer Council Queensland since the SunSmart school program is a sun-protection campaign of the Australian Cancer Council. School characteristics (for example, school ownership, school location and student enrolment figures) were obtained from the Education Queensland website. The Australian 'My School' website was used to retrieve the 'Index of community socio-educational advantage' values and student enrolment figures for schools not listed on the Education Queensland website (non-government owned schools).

Study designs: Studies 1 and 2 were cross-sectional studies. The comprehensiveness of north Queensland primary school sun-protection policies and the body surface area covered by regulation school uniforms of these schools were assessed using publicly available school sun-protection policies and uniform documents respectively. Sunprotection policies were independently reviewed using the minimum inclusion criteria outlined in the Cancer Council's 'guide to being SunSmart' resource (study 1). A maximum score of 12 was possible and the total score determined policy comprehensiveness. Pre-determined body region percentages were used to calculate the body surface area covered by regulation uniforms (study 2). The maximum possible body surface area was 93.4% since the head region was excluded from calculations.

Study 3 was a method comparison study of two shade measurement methods. WebShade®, a shade-planning computer software, was used to measure shade at a sample of north Queensland primary schools using the on-site shade-audit method provided by the WebShade® developers. The shade-audit method required data collection at schools including building dimensions and tree heights to measure shade. WebShade® was then used to estimate shade availability at schools using a remote shade-estimation method which we had developed in conjunction with WebShade®. The remote method used a series of pre-defined height values in place of on-site data collection to measure shade. Statistics of concordance were used to assess the agreement between values calculated for 11am and 1:30pm on the 1st of December, March, June and September, respectively, using the on-site shade-audit and remote shade-estimation methods.

Studies 4 and 5 were observational studies. The proportions of students and adult rolemodels wearing hats were observed at Townsville primary schools (study 4). Hat use was observed before, during and after school hours. The type of hat worn by students was classified as 'gold standard hat' (broad-brimmed, legionnaire or bucket style hats) or 'other hat' (for example, cap or visor style). The proportions of student spectators wearing hats (any hat type) and wearing shirts (swim-shirts/t-shirts) were observed at inter-primary-school swimming carnivals held in Townsville (study 5).

Results: Study 1: Sun-protection policies for 112 of 116 schools (96.6% participation rate) were evaluated. Although policies of Cancer Council accredited SunSmart schools addressed more environmental, curriculum and review-related criteria than those of non-SunSmart schools, the overall median score for both groups was low at 2 from a possible 12 (SunSmart schools: [Inter-quartile range (IQR): 2.0, 9.0], and non-SunSmart schools: [IQR:2.0, 3.0], p=0.008). Most policies included a 'no hat, no play' rule (that is, a rule that students are not permitted to play outdoors without a hat on). Criteria related to shade provision at outdoor events, regular policy review and using the policy to plan outdoor events were poorly addressed by most schools. No relationships were found between sun-protection policy scores and socio-economic status, school size, school locality or region.

Study 2: Uniform policies for 114 of 116 schools (98.3% participation rate) were evaluated. The average total body surface area covered by uniforms (overall 62.4% (standard deviation (SD): 1.8%) was found to be influenced by school grouping variables, such as school ownership and socio-educational status, however the differences in terms of skin coverage were small. For example, the uniforms of non-government schools covered more skin than those of government schools (63.2% (SD: 2.7%) and 62.0% (SD: 1.0%), respectively, p<0.001) and the uniforms of socio-educationally advantaged schools covered more skin than those of socio-educationally disadvantaged schools (62.8% (SD: 2.7%) and 62.3% (SD: 1.4%), respectively, p<0.001). SunSmart and non-SunSmart school uniforms covered identical total body surface proportions (62.4% (SD: 1.6%) and 62.4% (SD: 2.2%), respectively, p=0.084).

Study 3: Shade-related data were compared for 22 of 27 schools (81.5% participation rate). Shade-related values calculated using the remote shade-estimation method (offsite) were usually lower than the values calculated using the shade-audit method (onsite). The average differences between shade-audit values and remote shade-estimation values were 1.3% (SD: 7.6%) for natural shade, 3.7% (SD: 4.7%) for built shade and 5.1% (SD: 6.6%) for combined shade (that is, natural shade plus built shade) for 11am 1st December values. Agreement between natural, built and combined shade-related data were poor (Lin's concordance correlation coefficient (CCC) values all below 0.90). Agreement between the remote shade-estimation and shade-audit methods was poorest for built shade. For example, built shade CCC values for 11am 1st December ranged from -0.35 (95% CI: -0.70 to 0.14) to 0.01 (95% confidence interval (CI): -0.25 to 0.26).

Study 4: Observations were based on 36 of 46 schools (78.3% participation rate). Overall, a median of 52.2% (IQR: 45.4%, 59.8%) of 28,775 students and 47.9% (IQR: 38.1%, 58.2%) of 2,954 adults were observed wearing any type of hat. A median of 22.5% (IQR: 16.8%, 33.4%), 23.4% (IQR: 15.0%, 34.6%) and 92.9% (IQR: 84.9%, 95.6%) students were observed wearing hats (any styles) before, after and during school hours, respectively. Proportions of students observed to wear hats (any style and goldstandard hat styles) at school before, after and during school hours were similar at SunSmart and non-SunSmart schools. More students from non-government owned schools than government owned schools were usually observed wearing hats, including gold-standard hats, however the differences were not consistently significant. Most adults at SunSmart and non-SunSmart schools wore hats (any styles) during school hours (88.8% (IQR: 62.5%, 100.0%) and 80.6% (IQR: 41.7%, 94.4%), respectively, p=0.169). However fewer adults at SunSmart schools wore hats before school than adults at non-SunSmart schools (3.7% (IQR: 0.5%, 7.7%) Vs 10.2% (IQR: 5.3%, 17.1%), respectively, p=0.035). The proportions of adults who wore hats before, during and after school hours were not found to be significantly influenced by other school characteristics, including school ownership and total sun-protection policy score, considered.

Study 5: Observations were based on students from 41 of 46 schools (89.1% participation rate). Overall, a median of 30.7% (IQR: 13.2%, 46.7%) student spectators were observed wearing a hat and 77.3% (IQR: 70.0%, 85.9%) were observed wearing a shirt. Students from non-government schools were twice as likely as students from government schools to wear a hat (41% (IQR: 30.3%, 57.9%) and 18.2% (IQR: 9.8%, 37.9%), respectively, p=0.003). More students from SunSmart than non-SunSmart schools wore hats (36.3% (IQR: 13.0%, 48.8%) and 23.6% (IQR: 12.3%, 37.1%), respectively) however this difference was not significant (p=0.422). Neither the hat nor the shirt-wearing behaviours of student spectators were significantly influenced by their school's size (number of students), socio-educational advantage or the total sunprotection policy score.

Implications: The results of study 1 revealed that most primary schools in north Queensland have written sun-protection policies, however the comprehensiveness of these policies could be improved. These school communities may require support and advice to develop and implement sun-protection policies.

The results of study 2 showed that most school uniforms assessed could be modified to include longer shirt, sleeve, and pant hem lengths so that more of the body is covered by clothing. Protecting children's skin from over-exposure to ultraviolet radiation might reduce naevi development during childhood therefore sun-protective school uniforms should be worn by primary school students when outdoors.

The results of study 3 revealed that measuring shade at schools can be laborious. Future studies are needed to develop an improved remote shade-estimation method which might include contacting school communities to determine the dimensions of school buildings and trees as well as the locations of school boundaries. An improved remote shade-estimation method should be evaluated against the shade-audit method, or a goldstandard method for measuring shade when it becomes available.

The results of study 4 showed that hats are under-utilised by students and their adult role-models (including school staff and parents) when they are outdoors at school, especially before and after school hours. Children and adults, particularly parents accompanying their child to and from school, might require regular reminders to wear their hats. SunSmart status was not found to be a consistent predictor of higher student or adult hat-wearing proportions despite the 'no hat, no play' rule being a key element of the SunSmart school program.

The results of study 5 revealed that hats are under-utilised by student spectators at swimming carnivals. More student spectators could be encouraged to wear both hats and shirts since a single form of sun-protection will not protect an individual from both direct and indirect ultraviolet radiation at swimming events. For example, a hat alone will not protect students from both overhead sun-exposure (direct) and ultraviolet radiation which has been reflected off water surfaces and into seating areas (indirect).

Recommendations:

• Investigate the SunSmart school application and renewal process since SunSmart status was not a consistent predictor of improved sun-protection policies and sun-protective behaviours.

• Use qualitative research methods, for example focus groups, to investigate why sun-protection policies at schools were under-developed.

• Work with school communities to develop their sun-protection policies, possibly by ensuring they have access to suitable sun-safety resources and incentives (for example, a reward scheme) to develop and implement thorough policies.

• Encourage school communities to use their updated (comprehensive) sunprotection policies when planning outdoor activities at school (for example, outdoor physical activity classes) and at school related events (for example, swimming carnivals).

• Investigate the practicalities of introducing a sun-protective school uniform at north Queensland primary schools. This might involve using qualitative research methods, such as focus group discussions, to investigate if school communities would be willing to introduce a sun-safe uniform and if parents would be willing to purchase a sun-safe uniform.

• Design a sun-protective school uniform (for example, garments constructed with very high ultraviolet protection factor rated materials which include longer sleeve and pant hem lengths).

• Continue to observe and report the sun-protective behaviours of north Queensland primary school students and their adult role-models at schools and at school sport events.

• Introduce and evaluate a school-based sun-protection program that includes regular unannounced observations of sun-protective behaviours and rewards school communities that demonstrate a commitment to sun-safety.

• Design an improved remote method for measuring shade at schools based on the data and knowledge accumulated during this thesis.

• Evaluate the agreement of the improved remote shade-estimation method against established methods of measuring shade.